<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      color: red;
    }

    /* 这里把 html body div span li 等等的标签都改为了红色 */
  </style>
</head>

<body>
  <div>我的</div>
  <span>我的</span>
  <ul>
    <li>还是我的</li>
  </ul>
</body>

</html>